1,3,4-triazine-based derivatives are a subgroup of the triazines and many of them exhibit herbicidal activity and have been synthesized and widely used to protect crop against weeds. More recently, a novel 1,3,4-triazine based derivative was reported by SHIBAYAMA, Atsushi, et al in WO 2012/002096 A.
1,3-diethyl 2-(2-methylhydrazinylidene)propanedioate (the “DMP”) is an important intermediate compound for the preparation of the 1,3,4-triazine based derivatives and that is used mainly to form the 1,3,4-triazine ring. With respect to the preparation of the DMP, the diethyl malonate is often used as a starting raw material and first converted to diethyl ketomalonate. Then, the resultant diethyl ketomalonate is to react with methylhydrazine to obtain DMP. One shortcoming of this process is the involvement of the conversion from diethyl malonate to diethyl ketomalonate, which by nature is a hazardous oxidation reaction and involves undesired complicated side reactions. Thus, there is still a strong need for the provision of a more efficient and effective process for the preparation of the DMP in avoidance of the stated shortcoming.